Rich in active gases or metals — a strong mineral character.
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
FerBicarbonatesManganèse
Midori Onsen, in Satsuma, Kagoshima, draws iron-rich water at 42°C. The bathhouse offers an indoor bath, an outdoor rotenburo bath and a sauna, in a quiet corner of southern Kyushu.
Insider tip — Midori Onsen rises in the Satsuma Peninsula, where Kagoshima's volcanic substrate feeds iron-rich springs beloved for their deep-warming properties and faint metallic character. The name meaning green evokes the lush subtropical vegetation that frames the bathhouse, creating a verdant retreat just a short drive from Kagoshima City. The rotenburo is particularly atmospheric on misty mornings when Sakurajima can be glimpsed across the bay.